[1] Regarding work vehicles, the conventional techniques disclosed in JP 2004-242558A (hereinafter referred to as Patent Document 1) and JP 2003-59541A (hereinafter referred to as Patent Document 2) exist.
There are techniques according to which it is possible to select a charging mode in which power of a power generator driven by an engine is accumulated in a battery, or an assist mode in which the power accumulated in the battery is used as power for a work apparatus (e.g., see Patent Document 1).
Some passenger vehicles have a configuration in which a large-sized battery pack is mounted on a body floor portion of the vehicle, separate from an engine included in the hood (e.g., see Patent Document 2), although this configuration is not equivalent to that of a work vehicle.
[2] Conventionally, there have been known to be hybrid work vehicles that use an engine and an electric motor as drive sources, and electric work vehicles that use only an electric motor as a drive source. For example, the work vehicle disclosed in JP 2014-133489A (hereinafter referred to as Patent Document 3) is already known as such a work vehicle. A motor for auxiliary power is included in addition to an engine in the work vehicle disclosed in Patent Document 3. The work vehicle is run by the motor at a time of low speed, and is run by the engine (or by the engine and the motor) at a time of high speed.